From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 681513126D0; Wed, 15 Apr 2026 02:49:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776221380; cv=none; b=Rh8up2qFaGQwYLgU+MM9nDiqIq0Noa5qVsZEq/OFEMTgIwHP+Pde9RRZzXitE6DxSAX7MYA2ja7vL5Qe+gyvETnliD3nmnSF/Lo8mn4WaS3qsrWVZQXdcHxT4lRfVDm33ILcyyt56FW+Obx0KIsmaLlwy0lPS5ll2a4jF4jJZPY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776221380; c=relaxed/simple; bh=0AuenaOfmDE99zOKcXCll7vxX25cPALTWSc7lA12r8I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ne1agljSJhoO917YV2sURDHdA80yVEpBSe7AxA/FVh4R0roBIbGuqv7hiwmlxA3E6HWiqVsaY0hQf8gZNu1v88rBmYDPthKpHI+QTWM9pDWrJHV/ajxeirXWYoCwxJ5xveDEOkuoJCritEx3y94hF53bM55i+CbZReyzraKI3ww= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NC5av1rK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NC5av1rK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D342C19425; Wed, 15 Apr 2026 02:49:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776221380; bh=0AuenaOfmDE99zOKcXCll7vxX25cPALTWSc7lA12r8I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NC5av1rK5RQMpd3VkE01VXX28D1NScamat3D2yU/BLI8M1aEWTiYwpWiegGHcWJYL 5D7bg6J7MBdvO3JFbWT81/VtG6f4XuKg7OW8dvX8Saggo+z1MD4VfhrDpMj3si+Hx0 cGziEv8MqIqcr3UENYdXBhswntrvfMSlkmgw6vIpGzZB/tS7X2XJ5nGIptdpmgMEi3 MRATSuz3y+uSYhyvRJbPgaLQ0/Z3OeI3+b77lRiNP80EFPL3XLBdriGjt5du1mzSSm Uf3wTYkuMu7h5Ze2RdLHRqSDbY5BFDLDnVpFXR9XPTY0Sz3th2WGiEkAwNyVT6j2tT 63CLqfkHl62lg== Date: Wed, 15 Apr 2026 05:49:36 +0300 From: Jarkko Sakkinen To: "Li,Rongqing(ACG CCN)" Cc: Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "x86@kernel.org" , "H . Peter Anvin" , Kai Huang , "linux-sgx@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: =?utf-8?B?562U5aSNOiBbUEFUQ0hdW3YyXSB4?= =?utf-8?Q?86=2Fsgx?= =?utf-8?Q?=3A?= Use list_for_each_entry_srcu() for mm_list traversal Message-ID: References: <20260226014014.2541-1-lirongqing@baidu.com> <484ff5a62fee43618b30bbafb1ab3723@baidu.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <484ff5a62fee43618b30bbafb1ab3723@baidu.com> On Tue, Apr 14, 2026 at 07:47:54AM +0000, Li,Rongqing(ACG CCN) wrote: > > > > From: Li RongQing > > > > In commit 1728ab54b4be ("x86/sgx: Add a page reclaimer") (v5.11), > > list_for_each_entry_rcu() was used to traverse the enclave's mm_list. > > However, this is incorrect because the list is protected by a Sleepable RCU (SRCU) > > lock (encl->srcu). > > > > Since commit 28875945ba98 ("rcu: Add support for consolidated-RCU reader > > checking") (v5.4), RCU lockdep checking has become stricter. When > > CONFIG_PROVE_RCU is enabled, using the standard list_for_each_entry_rcu() > > while only holding an SRCU lock triggers "suspicious RCU usage" false positive > > warnings, as it does not recognize SRCU read-side critical sections. > > > > Fix this by switching to list_for_each_entry_srcu(), which was introduced > > specifically for this purpose in commit ae2212a7216b > > ("rculist: Introduce list/hlist_for_each_entry_srcu() macros") (v5.10). > > This correctly associates the traversal with the SRCU lock and eliminates the > > lockdep warnings. > > > > Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer") > > Signed-off-by: Li RongQing > > Acked-by: Kai Huang > > --- > > Ping > > thanks > > [Li,Rongqing] > > > > > Diff with v1: rewrite changelog > > > > arch/x86/kernel/cpu/sgx/encl.c | 12 ++++++++---- > > arch/x86/kernel/cpu/sgx/main.c | 3 ++- > > 2 files changed, 10 insertions(+), 5 deletions(-) > > > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > > index ac60ebd..91362d7 100644 > > --- a/arch/x86/kernel/cpu/sgx/encl.c > > +++ b/arch/x86/kernel/cpu/sgx/encl.c > > @@ -822,7 +822,8 @@ static struct sgx_encl_mm *sgx_encl_find_mm(struct > > sgx_encl *encl, > > > > idx = srcu_read_lock(&encl->srcu); > > > > - list_for_each_entry_rcu(tmp, &encl->mm_list, list) { > > + list_for_each_entry_srcu(tmp, &encl->mm_list, list, > > + srcu_read_lock_held(&encl->srcu)) { > > if (tmp->mm == mm) { > > encl_mm = tmp; > > break; > > @@ -933,7 +934,8 @@ const cpumask_t *sgx_encl_cpumask(struct sgx_encl > > *encl) > > > > idx = srcu_read_lock(&encl->srcu); > > > > - list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) { > > + list_for_each_entry_srcu(encl_mm, &encl->mm_list, list, > > + srcu_read_lock_held(&encl->srcu)) { > > if (!mmget_not_zero(encl_mm->mm)) > > continue; > > > > @@ -1018,7 +1020,8 @@ static struct mem_cgroup > > *sgx_encl_get_mem_cgroup(struct sgx_encl *encl) > > */ > > idx = srcu_read_lock(&encl->srcu); > > > > - list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) { > > + list_for_each_entry_srcu(encl_mm, &encl->mm_list, list, > > + srcu_read_lock_held(&encl->srcu)) { > > if (!mmget_not_zero(encl_mm->mm)) > > continue; > > > > @@ -1212,7 +1215,8 @@ void sgx_zap_enclave_ptes(struct sgx_encl *encl, > > unsigned long addr) > > > > idx = srcu_read_lock(&encl->srcu); > > > > - list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) { > > + list_for_each_entry_srcu(encl_mm, &encl->mm_list, list, > > + srcu_read_lock_held(&encl->srcu)) { > > if (!mmget_not_zero(encl_mm->mm)) > > continue; > > > > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > > index 38b7fd2..581e0c4 100644 > > --- a/arch/x86/kernel/cpu/sgx/main.c > > +++ b/arch/x86/kernel/cpu/sgx/main.c > > @@ -120,7 +120,8 @@ static bool sgx_reclaimer_age(struct sgx_epc_page > > *epc_page) > > > > idx = srcu_read_lock(&encl->srcu); > > > > - list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) { > > + list_for_each_entry_srcu(encl_mm, &encl->mm_list, list, > > + srcu_read_lock_held(&encl->srcu)) { > > if (!mmget_not_zero(encl_mm->mm)) > > continue; > > > > -- > > 2.9.4 > Reviewed-by: Jarkko Sakkinen BR, Jarkko